package demo3;

/**
 * 买卖股票的最佳时机 IV
 */
public class test8 {
    public int maxProfit(int k, int[] prices) {
        // 创建dp表
        int n = prices.length;
        k = Math.min(k,n/2);
        int[][] f = new int[n][k+1];
        int[][] g = new int[n][k+1];
        // 初始化
        int INF = 0x3f3f3f3f;
        for (int j = 0; j <= k; j++) {
            f[0][j] = g[0][j] = -INF;
        }
        f[0][0] = -prices[0];
        g[0][0] = 0;

        for (int i = 1; i < n; i++) {
            for (int j = 0; j <= k; j++) {
                f[i][j] = Math.max(f[i-1][j],g[i-1][j]-prices[i]);
                g[i][j] = g[i-1][j];
                if(j>=1){
                    g[i][j] = Math.max(g[i][j],f[i-1][j-1]+prices[i]);
                }
            }
        }
        int ret = 0;
        for (int j = 0; j <= k; j++) {
            ret = Math.max(ret,g[n-1][j]);
        }
        return ret;
    }
}
